This invention relates to a diesel fuel injector and more specifically to an injector which incorporates a heating apparatus for atomizing diesel fuel as it is directly injected into a cylinder or pre-chamber of an engine.
With regard to diesel engines it is appreciated that combustion is enhanced by delivering finely atomized fuel to the combustion chamber.
U.S. Pat. No. 4,345,555 mixes fuel with incoming air upstream of the cylinder. Fuel is heated by continuously supplying electrical energy to an ignition plug. In contrast, the present invention contemplates a vapor phase injector positioned directly within a cylinder or prechamber thereof. The injector includes a ceramic nozzle which finely atomizes the fuel. Atomization is enhanced by neating the nozzle to a predetermined temperative during engine start up. Once the engine is running the nozzle need not be heated by electrical means, since the nozzle it will absorb heat from the combustion process.
It is an object of the present invention to finely atomize fuel by injecting same through a heated nozzle. Another object of the present invention is to use the heat of the combustion process to heat the nozzle. An additional object of the present invention is to provide a nozzle having a predetermined temperature gradient thereacross.
Accordingly, the invention comprises:
A fuel injector, system and method comprising means for ejecting fuel into an engine through a non-conductive, heat storing element. The element including a nozzle portion comprising a preferably ceramic body having a narrow, first passage in communication with a conical second portion. The two portions cooperating to cause the fuel to flow turbulently therethrough. The nozzle further includes a heater for elevating the temperature to the nozzle to a predetermined temperature. In this manner, as the fuel contacts the heated nozzle it is atomized. In one embodiment of the invention a solid ceramic body is employed. In another embodiment, the nozzle is formed by a plurality of stacked ceramic disks which include a central opening therethrough and a plurality of heating elements, one for each disk. The openings are sized to approximate the continuous conical portion of the solid body nozzle. Means are provided for electrically heating the nozzle during certain operating intervals of the engine and a method of operating the engine is described which permits the removal of the electrical energy and permits the nozzle to thereafter be heated by the heat of the combustion process in the cylinder.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.